1. Field of the Invention
The present invention relates to a method for manufacturing a shaft-hub connection between a brake disk having a hub and a drive shaft having a bell.
2. Related Technology
Shaft-hub connections are used in mechanical engineering, particularly in the construction of vehicles. Apart from a large number of requirements, the essential task of such connections is the transmission of torque, mostly high torques. At the same time, it is desired that the shaft-hub connection be compact and lightweight and be assembled without extensive setting and adjusting work.
On the other hand, it is essential that the connection not allow relative movements between the shaft and the hub, i.e. even when no torque is transmitted, the connection needs to be free from backlash.
Further, the connected parts need to be connected in an ideally concentric and positioned manner. If they fail to meet this requirement, the resulting true running faults and wobble faults will cause unwanted noise and vibrations. In particular, when the vehicle is front-wheel driven, the wobble of a brake disk can cause vibrations in the steering wheel, and such inaccuracies resulting from the machining can be felt on the brake pedal.
Numerous approaches and developments to overcome the problems mentioned above are known. DE 198 36 259 A1, for example, describes a radial pressing device that presses the shaft-hub connection in the direction of a rotational axis in such a manner that the inner contour of the hub is in non-backlash engagement with the shaft. One drawback of this method is the necessity of additional components, requiring more space and, most of all, higher manufacturing cost.
The same applies to so-called tension set connections as known, for example, from DE 36 36 393 A1.
The use of wedge-shaped elements being inserted between the shaft and the hub is also known. However, these elements cause an eccentricity of the shaft and, hence, punctual and/or relatively small contact surfaces between the shaft and the hub.
A connection comprising so-called splines, being arranged in the region of the contact surfaces between the shaft and the hub, is widely known and practical as well. Such splines are protrusions on the shaft engaging into corresponding cavities of the hub. The manufacturing of such a connection is relatively costly because the protrusions and cavities have to engage exactly to provide, as far as possible, a connection without backlash. In this process, the shaft and the hub, i.e. the brake disk and the drive shaft, are at first prepared by so-called green machining or rough turning. In this stage, it is not yet possible to reach the final size and dimensions. The brake disk or hub requires further fine turning and broaching in subsequent steps, followed by clearing, burring, and finally checking for possible faults. The splines are formed onto the shaft by rolling, followed by hardening the shaft. Further hard finishing of the splines is no longer possible, i.e. any existing deformations due to hardening cannot later be compensated. The next step in the process is the so-called crack detection to detect any manufacturing faults. This entire manufacturing process is very difficult and hence expensive and requires the part to be checked and set in multiple turning machines.
EP 0 921 018 A1 discloses a wheel construction in which the end of the drive shaft facing the wheel is directly coupled with the brake body by means of a shaft portion having a polygonal outer contour. The brake body, or the brake disk, has a corresponding inner contour so as to form a concentric slaving portion. Basically, this wheel construction has a relatively small backlash, provided it has been exactly manufactured. This manufacturing means, an important requirement to be met by the manufacturing process, is not described in detail in EP 0 921 018 A1.